For hair styling, it matters whether or not the hair spreads, flows, or curls as intended, whether or not there are any hairs straying from the flow (i.e., so-called frizzy hairs), whether or not the initial styling lasts stably regardless of humidity, etc. A variety of styling aids, relaxors, perm solutions, and the like have thus been developed.
There have been developed instruments for measuring such physical properties as the thickness, tensile strength, and moisture content of each strand of hair, as well as an observation instrument for performing an image analysis on cuticle, cortex, medullar, and so on (Patent Document 1). There has been no apparatus, however, that displays the state of overall styling of hair clearly for objective evaluations. For that reason, styling aids and the like have been evaluated almost exclusively through actual use and sensory evaluations for disorder of hairstyles (Patent Document 2).
[Patent Document 1] JP-A-2000-287953
[Patent Document 2] JP-A-H11-92346